A hundred and fifty-one patients with congenital heart disease less than 24 months old underwent intracardiac repairs from January 1982 to July 1983, which consists 24.2% of all the patients with congenital heart diseases operated during the same period. There were 98 patients[64.9%] with acyanotic congenital heart disease and 53 patients[35.1%] with cyanotic congenital heart disease, and 55 patients[36.4%] were less than 1 year of age. Twenty-two patients died within 30 days after surgery and 3 patients died after postoperative 30th day: Ventricular septal defect, four of 90 patients; Tetralogy of Fallot, five of 23 patients; Transposition of great arteries, nine of 17 patients; Tricuspid atresia, four of 5 patients; Pulmonary atresia, all of 2 patients; Single ventricle, one of single patients. Over all mortality was 16.6% and mortality of acyanotic congenital heart disease, cyanotic congenital heart disease and patients less then 1 year of age was 4.1%, 39.6% and 20.0% respectively. Still the mortality of cyanotic congenital heart disease is high. Careful preoperative evaluation of the detailed intracardiac anatomy and hemodynamics of the patients and proper selection of surgical treatment yield better clinical results. [KTCS 1983;4:431-443]